* * * * * * Grain size: The obsidian has no grain size because the rock is glassycolor: blackHow it forms: The obsidian is a natural glass that is naturally formed from molten magma, associated with volcanoes.
This rock does not contain any fossils it is not an organic rock it is an igneous rock
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Grain size: The obsidian has no grain size because the rock is glassy color: black How it forms: The obsidian is a natural glass that is naturally formed from molten magma, associated with volcanoes.